Is it worth buying missing NI years? The break-even maths.
Class 3 voluntary NI contributions let you buy back missing years in your NI record. The cost is fixed; the benefit is a higher state pension for the rest of your life. For most people the return is exceptional. But not for everyone — and the rules tightened on 5 April 2025.
- ▸One missing NI year costs £956.80 to buy back via Class 3 voluntary contributions (2026/27 rate). It adds approximately £6.89/week (£359/yr) to your state pension — a break-even of about 2.7 years.
- ▸If you live to average life expectancy you will collect roughly 20 years of state pension. A single bought year returns over £7,000 at today's rates — before triple lock increases.
- ▸The extended window allowing top-ups back to 2006/07 closed on 5 April 2025. The standard six-year rule now applies. In 2026/27, the earliest fillable year is 2020/21 (deadline 5 April 2027). Anything older is permanently unrecoverable.
- ▸Buying years is less compelling if you already have 35 qualifying years, if you are likely to get credits before retirement anyway, or if you are in very poor health.
- ▸Use our NI gap top-up calculator to model the exact numbers for your own situation.
The cost of a missing NI year
Class 3 voluntary NI contributions are the standard mechanism for plugging gaps. For 2026/27 the rate is £18.40 per week — or £956.80 for a full year (52 × £18.40).
Historical gap years can usually be filled at the rate that applied in that year, which is often cheaper than the current rate. However, HMRC simplifies this and you should check the actual cost for each specific gap year via your personal NI record on gov.uk or by calling HMRC.
The rate rises modestly each year in line with policy, so gaps bought now will generally be cheaper than the same gaps bought in future years.
The return: extra state pension for life
Every qualifying year you add moves your state pension entitlement by one thirty-fifth of the full amount.
The full new state pension in 2026/27 is £241.30 per week. One thirty-fifth of that is £6.89 per week, or approximately £359 per year.
That £359 per year is paid for the rest of your life from state pension age. It is also uprated annually by the triple lock — the higher of earnings growth, CPI inflation, or 2.5% — so the real value of that extra income tends to grow over time.
The break-even calculation
Divide the cost by the annual gain:
£956.80 ÷ £359.00 = approximately 2.7 years
After just under three years of drawing the higher state pension, you have recovered the cost in nominal terms. Everything after that is pure gain.
To put it another way: if you reach state pension age and live for another 20 years (roughly average UK life expectancy from age 66), that one bought year returns:
20 × £359 = £7,180 in today's money — before triple lock uprating.
The after-tax picture is also worth considering. State pension counts as taxable income, but many people are below the personal allowance in retirement, meaning the extra state pension is received tax-free. Even for basic-rate taxpayers the after-tax return (roughly £287/yr) still breaks even in about 3.3 years.
No savings account, ISA, or annuity comes close to this rate of return for people who are in reasonable health.
The deadline for historical gap years — what changed in 2025
HMRC's extended window allowing top-ups back to 2006/07 closed on 5 April 2025. From 6 April 2025 onwards, the standard six-year rule applies again — only the most recent six tax years can be filled with voluntary Class 3 contributions.
In 2026/27 (the current tax year, running 6 April 2026 to 5 April 2027), the earliest tax year you can voluntarily fill is 2020/21. The deadline to fill the 2020/21 year is 5 April 2027. After that, 2020/21 falls outside the six-year window and becomes permanently unrecoverable.
The practical implication: if you discovered a gap from the 2006-2018 period, the window to fix it has now closed. If your gap is from 2020/21 onwards, you still have time, but the window is shorter than it used to be.
Use the state pension forecast calculator to see how your current record translates into a weekly amount, then use our NI gap top-up calculator to model the return on each gap year. Always check the current rules at gov.uk before assuming a gap is recoverable — historical exceptions and future extensions cannot be ruled out.
When it is NOT worth it
Buying missing NI years is not universally the right move. There are four situations where it may not make sense:
1. You already have 35 qualifying years. Additional years beyond 35 do not increase your state pension. If your record already shows 35 or more qualifying years — even with some gaps — filling those gaps is pointless.
2. You will accumulate enough years anyway. If you are in your 40s with 25 qualifying years and still working, you will likely reach 35 years naturally before retirement. Paying for years you will earn for free is wasteful.
3. You are in poor health. The break-even assumes you survive to collect. If you have serious health conditions that reduce life expectancy substantially, the calculation shifts. At under three years to break even the margin is still comfortable for most people, but if you are unlikely to draw the pension for more than a year or two it is harder to justify.
4. The year is already credited or will be credited. Some people assume they have a gap when actually a credit is pending — for example, if Child Benefit NI credits have not yet been applied to the record. Check the actual gap on gov.uk before paying to fill it.
- ▸Class 3 voluntary NI contributions cost £18.40/week (£956.80/year) for 2026/27, allowing gaps in your NI record to be filled. [gov.uk]
- ▸Each additional qualifying year adds 1/35th of the full new state pension — approximately £6.89/week (£359/yr) at 2026/27 rates. [gov.uk]
- ▸The extended window allowing top-ups back to 2006/07 closed on 5 April 2025. From 6 April 2025 onwards, only the most recent six tax years can be filled with voluntary Class 3 contributions. In 2026/27, the earliest fillable year is 2020/21. [gov.uk]
- ▸The full new state pension is £241.30/week (£12,548/yr) for 2026/27, uprated annually by the triple lock. [gov.uk]
Important — this is not financial advice
Pension Bible is a volunteer educational publication. We are not authorised by the Financial Conduct Authority to provide regulated financial advice, and nothing on this page constitutes a personal recommendation. The break-even maths above is general editorial illustration based on UK rules in force at the date of last review (shown in the page header). Whether buying NI years is right for you depends on your specific situation — your current NI record, expected retirement age, expected longevity, and other retirement income sources will all change the calculation.
Before paying voluntary Class 3 contributions:
- Check your personal NI forecast at gov.uk (Check your State Pension forecast) — this is the only source that knows your specific record, including any pending credits that you might assume are gaps.
- Call the Future Pension Centre (DWP, 0800 731 0181) before paying — they can confirm whether buying back specific years will actually increase your forecast.
- MoneyHelper (all ages) — free guidance via moneyhelper.org.uk.
- Pension Wise (over-50s) — free pension guidance via MoneyHelper.
- An FCA-regulated financial adviser — find one via Unbiased or VouchedFor.
Always verify the current rules and rates on gov.uk before paying — the deadline windows have changed multiple times in recent years, and may change again.